Welsh political party Plaid Cymru has lambasted the BBC for forcing its advertising boards to be taken down at rugby grounds.
Plaid says the BBC has no right to remove the ads as they are outdoors, and are therefore not broadcast sponsorship or advertising.
The party says BBC Wales ordered the ads, at four Welsh regional rugby team grounds, to be taken down in accordance with rules about party political advertising, ahead of May’s elections.
The BBC is believed to have told the clubs it could not air matches featuring the ads, which show an image of the Plaid logo.
A Plaid spokesman says: "The BBC must acknowledge that its actions have been out of order and have no grounding in any legislation or guidance."
Plaid has written to Mark Thompson, director-general of the BBC, and the BBC controller of Wales Menna Richards and says it will take further action or seek compensation if the matter is not resolved.
It adds that the Scottish National Party advertises on hoardings at Scottish football clubs, yet the BBC has not taken any action.